1. Field of Invention
The present invention relates to a nut driver, and more particularly to a driver for a brass cylindrical type nut applied to an electrical terminal.
2. Related Art
FIG. 1 is a schematic view of an electric valve actuator for use in a nuclear power plant. Referring to FIG. 1, the electric valve actuator 1 mainly has a valve actuator body 10, a terminal board 11 is provided on one side of the valve actuator body 10, and serves as a bridge interface between all electrical communication within the valve actuator body 10 and an external controller 12. An exterior surface of the terminal board is connected to a plurality of electrical lines 13, so as to be electrically connected to the controller 12.
FIG. 2 is a schematic cross-sectional view of the terminal board of the electric valve actuator. In FIG. 2, the terminal board 11 has a plurality of through holes, each through hole has a conductive screw 110, and threads 111 and 112 on both ends of the conductive screw 110 are respectively on two side surfaces of the terminal board 11. The thread 112 is responsible for electrical connection between electrical elements inside the valve actuator body 10, while the thread 111 is responsible for electrical connection with the external controller 12. An air-tight ring 113 is provided between each conductive screw 110 and the terminal board 11. Generally speaking, the thread 111 of the conductive screw 110 on one side of the terminal board 11 has a conductive collar 15, which is fitted on the thread 111 of the conductive screw 110 and then fastened to the conductive screw 110 by a nut 14. Similarly, a conductive collar is also fitted on the thread 112 on the other side of the terminal board 11 and then fastened by a nut.
In the prior art, when the electric valve actuator 1 is to be maintained, it is necessary to loosen and take out the nut 14 on the conductive screw 110 coupled to the controller 12 and then take down the conductive collar 15 to facilitate maintenance. However, even if the maintainer can loosen the nut 14 by hand, the nut 14 easily falls off from the hand and drops to the bottom of the valve actuator body 10 due to its small volume. Moreover, since the facility layout in the nuclear power plant is limited by space, it is difficult to pick up the dropped nut 14, which is also time-consuming.
In view of the above, a nut driver for an electrical terminal is needed to solve the problem in the prior art.